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PHYSICAL SCIENCES: CHEMISTRY (P2)

EXEMPLAR 2008

NATIONAL SENIOR CERTIFICATE

GRADE 12

Physical Sciences/P2 DoE/Exemplar 2008 NSC


2

INSTRUCTIONS AND INFORMATION 1. 2. 3. 4. 5. 6. 7. 8. 9.

Write your name and/or examination number (and centre number if applicable) in the appropriate spaces on the ANSWER BOOK, ANSWER SHEET and GRAPH PAPER. Answer ALL the questions. Answer SECTION A on the attached ANSWER SHEET. Answer SECTION B in the ANSWER BOOK. Answer QUESTION 6.2 on the attached GRAPH PAPER. Non-programmable calculators may be used. Appropriate mathematical instruments may be used. Number the answers correctly according to the numbering system used in this question paper. Data sheets and a periodic table are attached for your use. Wherever motivations, discussions, et cetera are required, be brief.



3

SECTION A Answer this section on the attached ANSWER SHEET. QUESTION 1: ONE-WORD ITEMS Give ONE word/term for each of the following descriptions. Write only the word/term next to the question number (1.1 – 1.5) on the attached ANSWER SHEET.

1.1 Compounds with the same molecular formula but different structural formulae (1) 1.2 The unstable intermediate compound formed during a chemical reaction (1) 1.3 An ionic solution that conducts electricity (1) 1.4 The reactant that donates electrons during a redox reaction (1) 1.5 The process of separating nitrogen from liquid air (1)

[5] QUESTION 2: MATCHING ITEMS Choose an item from COLUMN B that matches a description in COLUMN A. Write only the letter (A – J) next to the question number (2.1 – 2.5) on the attached ANSWER SHEET.

COLUMN A

COLUMN B

2.1 2.2 2.3 2.4 2.5

The functional group of an amide A substance that decreases the activation energy of a reaction Anode in an electrolytic cell Secondary cell Ostwald process

A

B

C

D

E

F

G

H

I

J

negative electrode ─ NH2 catalyst isomer dry cell positive electrode ammonia car battery nitric acid

[5]

O

─ C ─ NH2



4

QUESTION 3: TRUE OR FALSE Indicate whether the following statements are TRUE or FALSE. Choose the answer and write only 'true' or 'false' next to the question number (3.1 – 3.5) on the attached ANSWER SHEET. Correct the statement if it is FALSE.

3.1 The simplest ketone has three carbon atoms. (2) 3.2 A reaction reaches equilibrium when the concentrations of the products and

reactants are equal.

(2) 3.3 If sulphur dioxide reacts with oxygen in an open container, equilibrium is

reached after a while.

(2) 3.4 The reactions C(s) + O2(g) → CO2(g) and 2KCℓO3(s) → 2KCℓ(s) + 3O2(g) are

examples of redox reactions.

(2) 3.5 During the industrial preparation of chlorine and sodium hydroxide, chemical

energy is converted to electrical energy.

(2) [10]



5

QUESTION 4: MULTIPLE-CHOICE QUESTIONS Four possible options are provided as answers to the following questions. Each question has only ONE correct answer. Choose the answer and make a cross (X) in the block (A – D) next to the question number (4.1 – 4.5) on the attached ANSWER SHEET.

4.1 A simple reaction scheme is shown below. The formula for Y is … A

B C D

CH3CH2COOH CH3CHOHCH3 CH3CHBrCH2OH CH3CHOHCH2Br

(3)

4.2 The structural formulae for four compounds are shown below. These compounds can be classified in the correct sequence as … A

B

C

D

Carboxylic acid, amine, amide, aldehyde

Carboxylic acid, amide, aldehyde, amine

Aldehyde, amine, carboxylic acid, amide

Carboxylic acid, amine, aldehyde, amide

(3)

HBr(g)

reflux with CH3CH = CH2 X Y

NaOH(aq)

+ HBr

H C

O

H

H

C C N

H H

H

H H

H OH C

O

H C C

O H

NH2

H

H



6

4.3 The following reaction is in equilibrium in a closed container:

PCℓ5(g) ⇌ PCℓ3(g) + Cℓ2(g) ΔH < 0

Which ONE of the following statements regarding the equilibrium is TRUE?

A B C D

Addition of a catalyst favours the forward reaction. Increasing the temperature has no effect on the yield of products. An increase in the concentration of PCℓ5(g) causes an increase in the concentration of the products. Increasing the temperature causes the value of the equilibrium constant to increase.

(3)

4.4 Which statement is CORRECT for a Zn-Cu galvanic cell that operates under standard conditions?

A

B C D

The concentration of the Zn2+ ions in the zinc half-cell gradually decreases. The concentration of the Cu2+ ions in the copper half-cell gradually increases. Negative ions migrate from the zinc half-cell to the copper half-cell. The intensity of the colour of the electrolyte in the copper half-cell gradually decreases.

(3) 4.5 Which one of the following solutions can be stored in an aluminium container?

(Use the Table of Standard Reduction Potentials.)

A

B C D

CuSO4(aq) ZnSO4(aq) NaCℓ(aq) Pb(NO3)2(aq)

(3) [15]

TOTAL SECTION A: 35



7

SECTION B

INSTRUCTIONS

1. 2. 3.

Answer this section in the ANSWER BOOK. In ALL calculations the formulae and substitutions must be shown. Round off your answers to TWO decimal places.

QUESTION 5 Alcohols are used in a variety of chemical reactions and as preservatives in certain medicines. All alcohols are toxic. Although ethanol is the least toxic of all alcohols, it is still a poisonous substance. It is rapidly absorbed into the blood. High blood alcohol levels can cause brain poisoning. The body can reduce high blood alcohol levels by oxidising the alcohol. Contrary to what people believe, alcohol is a depressant and not a stimulant. The following table indicates the effects of various blood alcohol levels:

The effects of blood alcohol levels

% per volume Effect

0,005 – 0,15 Loss of coordination

0,15 – 0,20 Severe intoxication

0,20 – 0,40 Loss of consciousness

0,50 Death

The liver enzyme, ADH, catalyses the oxidation of ethanol to ethanal and then to non-toxic ethanoic acid. The liver is able to remove only 28 grams of pure alcohol per hour.

5.1 Write down the NAMES of the homologous series to which the compounds

ethanal and ethanoic acid respectively belong.

(2) 5.2 Write down the structural formula of ethanal. (2) 5.3 Alcohols are prepared by the hydration of alkenes. Use structural formulae

to write down the equation which represents the formation of ethanol.

(3) 5.4 The warning on the labels of certain medicines reads as follows:

The effect of this medicine is aggravated by the simultaneous intake of alcohol. Use the information in the passage above to justify this warning.

(4) [11]



8

QUESTION 6 The first six members of the alkanes occur as gases and liquids at normal temperatures. Alkanes are currently our most important fuels, but the use of alcohols as renewable energy source is becoming more and more important. Alcohols are liquids that might be a solution to the energy crisis.

6.1 Which chemical property of alkanes and alcohols make them suitable to be

used as fuels?

(2) 6.2 The table shows the boiling points of the first six alkanes and the first six

alcohols.

Alkane Boiling

point (°C) Alcohol

Boiling point (°C)

methane - 164 methanol 65

ethane - 89 ethanol 79

propane - 42 1-propanol 97

butane - 0,5 1-butanol 117

pentane 36 1-pentanol 138

hexane 69 1-hexanol 156

Draw a graph of boiling points versus number of carbon atoms for the first six

ALCOHOLS. Choose 50 °C and 1 carbon atom as origin and use an appropriate scale. Plot the points and draw the best curve through the points.

(5) 6.3 What trend in boiling point can be observed from the graph? (2) 6.4 Provide a reason for the trend mentioned in QUESTION 6.3 by referring to the

type of intermolecular forces.

(2) 6.5 Explain, referring to the type of intermolecular forces, why the boiling points of

alcohols are higher than the boiling points of alkanes.

(2) 6.6 People are always cautioned to keep liquids such as petrol (a mixture of

alkanes) out of reach of children. Use the boiling points of alkanes and justify this precaution.

(2)

6.7 Briefly explain why ethanol is a renewable energy source, while the alkanes

are non-renewable.

(2) [17]



9

QUESTION 7 Consider the organic compounds labelled A – E.

7.1 Write a balanced chemical equation for the preparation of compound D using

an alkane as one of the reactants.

(3) 7.2 Write down the IUPAC name for compound B? (2) 7.3 Write down the structural formula of an isomer of compound A that has only

FOUR carbon atoms in the longest chain. (2)

7.4 Write down the structural formula for compound C. (2)

[9]

A. CH3CH2CH2CH2CH2CH3

D. CH3 Cℓ

C. C6H6

E. Methylamine

H

H

H

H H

C H

C

H H

H

C

H

H

C

H

C

O

C

H

H

C

H

H

C

B.



10

QUESTION 8 A learner investigates the relationship between the mass of a metal and the volume of the gas produced when the metal reacts with dilute hydrochloric acid. During the investigation the learner adds the metal in amounts of 0,4 g to a certain volume of acid in a container. After the complete reaction between the metal and the acid, the learner measures the volume of gas that forms after each addition of the metal.

8.1 State a possible hypothesis for this investigation? (2) The learner plotted the graph shown below after conducting the investigation. 8.2 Name TWO variables that must be controlled during this investigation. (4) 8.3 What conclusion can be drawn from the section PQ on the graph? (2) 8.4 Use the graph to predict the volume of gas that will be produced when 0,4 g

of the metal reacts with the acid.

(2) [10]

0

50

100

150

200

250

300

400

Vo

lum

e o

f ga

s (

cm

3)

350

0 0,4 0,8 1,2 1,6 2,0 2,4

Mass of metal (g)

P Q



11

QUESTION 9 In general a teaspoonful of sugar dissolves much quicker in hot water than in the same amount of cold water. Use the graph below and your knowledge of the collision theory to explain this observation.

[5]

Kinetic energy

T1

T2

T2 T1

Minimum kinetic energy needed for a reaction to take place

Fra

ctio

n o

f m

ole

cule

s w

ith

a g

ive

n

kin

etic e

ne

rgy



12

QUESTION 10 In a limited supply of oxygen, such as in a car which is not tuned properly, octane burns incompletely to produce, amongst others, carbon monoxide. The following balanced chemical equation represents the reaction during which carbon monoxide forms:

2C8H18(ℓ) + 17O2(g) → 16CO(g) + 18H2O(g) ∆H < 0

The reaction can be represented by the potential energy graph below.

10.1 By comparing the activation energies of the forward and reverse reactions,

explain whether it will be easier to form products from reactants or reactants from products.

(2) 10.2 Use the chemical equation above and give a reason why vehicles with

incorrectly tuned engines are a health hazard.

(2) 10.3 Part of the action of catalytic converters is to speed up the complete oxidation

of carbon monoxide (CO) and petrol (C8H18) from incorrectly tuned engines according to the equations below.

2C8H18(ℓ) + 25O2(g) →16CO2 (g) + 18H2O(g) ……………… (i)

2CO(g) + O2 →2CO2(g)…………………………..…….…….. (ii) Why should people support legislation that makes catalytic converters a necessary component of exhaust systems of automobiles?

(2) [6]

reactants

products

Po

ten

tia

l en

erg

y

Course of reaction

Activated complex



13

QUESTION 11 11.1 Many industries use ammonia as a coolant in their plants. Ammonia is also

used in the fertiliser industry. The ammonia is manufactured by the Haber process in the presence of a catalyst at a temperature of 500 °C. The equilibrium process may be represented by the equation below.

N2(g) + 3H2(g) ⇌ 2NH3(g) ∆H <0

The temperature is now decreased to 100 °C.

Explain whether or not the ammonia can now be produced profitably.

(3) 11.2 Ammonia is used in the industrial preparation of nitric acid. One of the

reactions in this process, shown below, reached equilibrium in a closed container at a temperature of 1 000 °C.

4NH3(g) + 5O2(g) ⇌ 4NO(g) + 6H2O(g) The initial concentrations of NH3(g) and O2(g) were both equal to 1 mol∙dm-3. At equilibrium it is found that the concentration of NH3(g) has changed by 0,25 mol∙dm-3.

11.2.1

11.2.2

Calculate the value of the equilibrium constant (KC) at the given temperature. Is the yield of NO high or low at this temperature? Give a reason for your answer.

(9) (3) [15]



14

QUESTION 12

A dry cell, as shown in the diagram below, does not contain a liquid electrolyte. The electrolyte in a typical zinc-carbon cell is a moist paste of ammonium chloride and zinc chloride. The paste of ammonium chloride reacts according to the following half-reaction:

2NH 4 (aq) + 2e- → 2NH3(g) + H2(g) … (i)

Manganese(IV) oxide is included in the cell to remove the hydrogen produced during half-reaction (i), according to the following reaction:

2MnO2(s) + H2(g) ⇌ Mn2O3(s) + H2O(ℓ) ... (ii) The combined result of these two half-reactions can be represented by the following half reaction:

2NH 4 (aq) + 2MnO2(s) + 2e- ⇌ Mn2O3(s) + 2NH3(g) + H2O(ℓ) … (iii)

12.1 Explain why it is important that the hydrogen produced in half-reaction (i) is

removed by the manganese(IV) oxide.

(2)

In a zinc-carbon cell, such as the one above, half-reaction (iii) and the half-reaction that takes place in the Zn/Zn2+ half-cell, produce an emf of 1,5 V under standard conditions.

12.2 Write down the half-reaction occurring at the anode. (2)

12.3 Write down the net ionic equation occurring in the zinc-carbon cell. (2) 12.4 Calculate the reduction potential for the cathode half-reaction. (4)

12.5 When in use the zinc casing of the dry cell becomes thinner, because it is oxidised. When not in use, it still corrodes. Give a reason for the latter observation.

(2)

12.6 Dry cells are generally discarded when 'flat'. Why is the carbon rod the most useful part of the cell, even when the cell is flat?

(2) [14]

Metal cap (+)

Carbon rod

Manganese(IV) oxide

Moist paste of ammonium chloride and zinc chloride

Metal bottom (-)



15

QUESTION 13

13.1 Give TWO reasons why the membrane cell is the preferred cell for the

preparation of chlorine.

(2) 13.2 Why do you think it is advisable to use inert electrodes in this process? (2) 13.3 Write down the equation for the half-reaction taking place at electrode M. (2) 13.4 Which gas is chlorine gas? Write down only Gas A or Gas B. (2) 13.5 Briefly explain how sodium hydroxide forms in this cell. (3)

[11]

Chloralkali manufacturing process The chloralkali (also called 'chlorine-caustic') industry is one of the largest electrochemical technologies in the world. Chlorine is produced using three types of electrolytic cells. The simplified diagram below shows a membrane cell.

Gas A Gas B Power supply

NaOH

+ - N

Saturated NaCℓ(aq)

Depleted NaCℓ

M



16

QUESTION 14

Why we need fertilisers There is likely to be a gap between food production and demand in several parts of the world by 2020. Demand is influenced by population growth and urbanisation, as well as income levels and changes in dietary preferences. The facts are as follows:

There is an increasing world population to feed

Most soils in the world used for large-scale, intensive production of crops lack the necessary nutrients for the crops

Conclusion: Fertilisers are needed!

The flow diagram below shows the main steps in the industrial preparation of two important solid fertilisers.

14.1 Write down the balanced chemical equation for the formation of the brown

gas.

(3) 14.2 Write down the name of process Y. (2) 14.3 Write down the chemical formula of liquid E. (2) 14.4 Write down the chemical formulae of fertilisers C and D respectively. (4)

Fertiliser D

Liquid E

Ammonia (NH3)

Methane Air

Nitrogen Hydrogen

Haber process

NO Process Y

H2SO4 Fertiliser C Brown gas

Physical Sciences/P2 17 DoE/Exemplar 2008 NSC

Copyright reserved

The following extract comes from an article on fertilisers:

A world without food for its people – A world with an environment poisoned through the actions of man –

Are two contributing factors towards a disaster scenario.

14.5 Write down THREE ways in which the use of fertilisers poisons the

environment.

(6) [17]

TOTAL SECTION B:

GRAND TOTAL:

115 150



NATIONAL SENIOR CERTIFICATE

NASIONALE SENIOR SERTIFIKAAT

DATA FOR PHYSICAL SCIENCES GRADE 12 PAPER 2 (CHEMISTRY)

GEGEWENS VIR FISIESE WETENSKAPPE GRAAD 12

VRAESTEL 2 (CHEMIE) TABLE 1: PHYSICAL CONSTANTS/TABEL 1: FISIESE KONSTANTES

NAME/NAAM SYMBOL/SIMBOOL VALUE/WAARDE

Standard pressure Standaarddruk

p 1,013 x 105 Pa

Molar gas volume at STP Molêre gasvolume by STD

Vm 22,4 dm3∙mol-1

Standard temperature Standaardtemperatuur T 273 K

TABLE 2: FORMULAE/TABEL 2: FORMULES

M

mn

V

nc

MV

mc

θ

anode

θ

cathode

θ

cell EEE / θ

anode

θ

katode

θ

sel EEE

θ

oxidation

θ

reduction

θ

cell EEE / θ

oksidasie

θ

reduksie

θ

sel EEE

θ

agent reducing

θ

agent oxidising

θ

cell EEE / θ

ddelreduseermi

θ

ddeloksideermi

θ

sel EEE



TABLE 3: THE PERIODIC TABLE OF ELEMENTS TABEL 3: DIE PERIODIEKE TABEL VAN ELEMENTE

1 (I)

2 (II)

3

4

5

6

7

8

9

10

11

12

13 (III)

14 (IV)

15 (V)

16 (VI)

17 (VII)

18 (VIII)

2,1

1 H 1

2 He 4

1,0

3 Li 7

1,5

4 Be 9

2,0

5 B 11

2,5

6 C 12

3,0

7 N 14

3,5

8 O 16

4,0

9 F 19

10 Ne 20

0,9

11 Na 23

1,2

12 Mg 24

1,5

13 Aℓ 27

1,8

14 Si 28

2,1

15 P 31

2,5

16 S 32

3,0

17 Cℓ

35,5

18 Ar 40

0,8

19 K 39

1,0

20 Ca 40

1,3

21 Sc 45

1,5

22 Ti 48

1,6

23 V 51

1,6

24 Cr 52

1,5

25 Mn 55

1,8

26 Fe 56

1,8

27 Co 59

1,8

28 Ni 59

1,9

29 Cu

63,5

1,6

30 Zn 65

1,6

31 Ga 70

1,8

32 Ge 73

2,0

33 As 75

2,4

34 Se 79

2,8

35 Br 80

36 Kr 84

0,8

37 Rb 86

1,0

38 Sr 88

1,2

39 Y 89

1,4

40 Zr 91

41 Nb 92

1,8

42 Mo 96

1,9

43 Tc

2,2

44 Ru 101

2,2

45 Rh 103

2,2

46 Pd 106

1,9

47 Ag 108

1,7

48 Cd 112

1,7

49 In

115

1,8

50 Sn 119

1,9

51 Sb 122

2,1

52 Te 128

2,5

53 I

127

54 Xe 131

0,7

55 Cs 133

0,9

56 Ba 137

57 La 139

1,6

72 Hf

179

73 Ta 181

74 W

184

75 Re 186

76 Os 190

77 Ir

192

78 Pt

195

79 Au 197

80 Hg 201

1,8

81 Tℓ

204

1,8

82 Pb 207

1,9

83 Bi

209

2,0

84 Po

2,5

85 At

86 Rn

0,7

87 Fr

0,9

88 Ra 226

89 Ac

58 Ce 140

59 Pr

141

60 Nd 144

61 Pm

62 Sm 150

63 Eu 152

64 Gd 157

65 Tb 159

66 Dy 163

67 Ho 165

68 Er

167

69 Tm 169

70 Yb 173

71 Lu 175

90 Th 232

91 Pa

92 U

238

93 Np

94 Pu

95 Am

96 Cm

97 Bk

98 Cf

99 Es

100 Fm

101 Md

102 No

103 Lr

29

Cu 63,5

1,9

Symbol Simbool

Electronegativity Elektronegatiwiteit

Approximate relative atomic mass Benaderde relatiewe atoommassa

Atomic number Atoomgetal

KEY/SLEUTEL


Copyright reserved

TABLE 4A: STANDARD REDUCTION POTENTIALS/ TABEL 4A: STANDAARD REDUKSIEPOTENSIALE

Half-reactions/Halfreaksies θE (V)

F2(g) + 2e ⇌ 2F + 2,87

Co3+

+ e

⇌ Co2+

+ 1,82

MnO 4 + 8H+ + 5e ⇌ Mn

2+ + 4H2O + 1,52

Cℓ2(g) + 2e ⇌ 2Cℓ

+ 1,36

Cr2O2

7 + 14H+ + 6e ⇌ 2Cr

3+ + 7H2O + 1,33

MnO2 + 4H

+ + 2e

⇌ Mn

2+ + 2H2O + 1,28

O2(g) + 4H+ + 3e ⇌ 2H2O + 1,23

Br2(ℓ) + 2e

⇌ 2Br

+ 1,06

NO 3 + 4H+ + 3e ⇌ NO(g) + 2H2O + 0,96

Ag+ + e ⇌ Ag + 0,80

Hg2+

+ 2e ⇌ Hg(ℓ) + 0,78

NO 3 + 2H+ + e ⇌ NO2(g) + H2O + 0,78

Fe3+

+ e ⇌ Fe2+

+ 0,77

O2(g) + 2H+ + 2e ⇌ H2O2 + 0,68

I2 + 2e ⇌ 2I

+ 0,54

Cu+ + e ⇌ Cu + 0,52

SO2 + 4H+ + 2e ⇌ S + 2H2O + 0,45

2H2O + O2 + 4e ⇌ 4OH + 0,40

Cu2+

+ 2e ⇌ Cu + 0,34

SO2

4 + 4H+ + 4e ⇌ SO2(g) + 2H2O + 0,17

Cu2+

+ e ⇌ Cu+ + 0,16

Sn4+

+ 2e ⇌ Sn2+

+ 0,15

S + 2H+ + 2e

⇌ H2S(g) + 0,14

2H+ + 2e ⇌ H2(g) 0,00

Fe3+

+ 3e ⇌ Fe 0,04

Pb2+

+ 2e ⇌ Pb 0,13

Sn2+

+ 2e ⇌ Sn 0,14

Ni2+

+ 2e ⇌ Ni 0,25

Co2+

+ 2e ⇌ Co 0,28

Cd2+

+ 2e ⇌ Cd 0,40

Cr3+

+ e ⇌ Cr2+

0,41

Fe2+

+ 2e ⇌ Fe 0,44

Cr3+

+ 3e ⇌ Cr 0,74

Cr2+

+ 2e ⇌ Cr 0,74

Zn2+

+ 2e ⇌ Zn 0,76

2H2O + 2e ⇌ H2(g) + 2OH

0,83

Mn2+

+ 2e ⇌ Mn 1,18

Aℓ3+

+ 3e ⇌ Aℓ 1,66

Mg2+

+ 2e ⇌ Mg 2,37

Na+ + e ⇌ Na 2,71

Ca2+

+ 2e ⇌ Ca 2,87

Ba2+

+ 2e ⇌ Ba 2,90

K+ + e ⇌ K 2,92

Li+ + e

⇌ Li 3,04

Inc

reas

ing

ox

idis

ing

ab

ilit

y/T

oen

em

en

de o

ks

ide

ren

de v

erm

oë

Inc

reas

ing

re

du

cin

g a

bilit

y/T

oen

em

en

de r

ed

us

ere

nd

e v

erm

oë


Copyright reserved

TABLE 4B: STANDARD REDUCTION POTENTIALS/ TABEL 4B: STANDAARD REDUKSIEPOTENSIALE

Half-reactions/Halfreaksies θE (V)

Li+ + e

⇌ Li 3,04

K+ + e ⇌ K 2,92

Ba2+

+ 2e ⇌ Ba 2,90

Ca2+

+ 2e ⇌ Ca 2,87

Na+ + e ⇌ Na 2,71

Mg2+

+ 2e ⇌ Mg 2,37

Aℓ3+

+ 3e ⇌ Aℓ 1,66

Mn2+

+ 2e ⇌ Mn 1,18

2H2O + 2e ⇌ H2(g) + 2OH

0,83

Zn2+

+ 2e ⇌ Zn 0,76

Cr2+

+ 2e ⇌ Cr 0,74

Cr3+

+ 3e ⇌ Cr 0,74

Fe2+

+ 2e ⇌ Fe 0,44

Cr3+

+ e ⇌ Cr2+

0,41

Cd2+

+ 2e ⇌ Cd 0,40

Co2+

+ 2e ⇌ Co 0,28

Ni2+

+ 2e ⇌ Ni 0,25

Sn2+

+ 2e ⇌ Sn 0,14

Pb2+

+ 2e ⇌ Pb 0,13

Fe3+

+ 3e ⇌ Fe 0,04

2H+ + 2e ⇌ H2(g) 0,00

S + 2H+ + 2e

⇌ H2S(g) + 0,14

Sn4+

+ 2e ⇌ Sn2+

+ 0,15

Cu2+

+ e ⇌ Cu+ + 0,16

SO2

4 + 4H+ + 4e ⇌ SO2(g) + 2H2O + 0,17

Cu2+

+ 2e ⇌ Cu + 0,34

2H2O + O2 + 4e ⇌ 4OH

+ 0,40

SO2 + 4H+ + 2e ⇌ S + 2H2O + 0,45

Cu+ + e ⇌ Cu + 0,52

I2 + 2e ⇌ 2I + 0,54

O2(g) + 2H+ + 2e ⇌ H2O2 + 0,68

Fe3+

+ e ⇌ Fe2+

+ 0,77

NO 3 + 2H+ + e ⇌ NO2(g) + H2O + 0,78

Hg2+

+ 2e ⇌ Hg(ℓ) + 0,78

Ag+ + e ⇌ Ag + 0,80

NO 3 + 4H+ + 3e ⇌ NO(g) + 2H2O + 0,96

Br2(ℓ) + 2e

⇌ 2Br + 1,06

O2(g) + 4H+ + 3e ⇌ 2H2O + 1,23

MnO2 + 4H

+ + 2e

⇌ Mn

2+ + 2H2O + 1,28

Cr2O2

7 + 14H+ + 6e ⇌ 2Cr

3+ + 7H2O + 1,33

Cℓ2(g) + 2e ⇌ 2Cℓ

+ 1,36

MnO 4 + 8H+ + 5e ⇌ Mn

2+ + 4H2O + 1,52

Co3+

+ e

⇌ Co2+

+ 1,82

F2(g) + 2e ⇌ 2F + 2,87

Inc

reas

ing

ox

idis

ing

ab

ilit

y/T

oen

em

en

de o

ks

ide

ren

de v

erm

oë

Inc

reas

ing

re

du

cin

g a

bilit

y/T

oen

em

en

de r

ed

use

ren

de

ve

rmo

ë


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PHYSICAL SCIENCES P2 GRADE 12 ANSWER SHEET

FISIESE WETENSKAPPE V2 GRAAD 12-ANTWOORDBLAD

QUESTION 1/VRAAG 1 QUESTION 2/VRAAG 2 1.1

(1)

2.1

(1)

1.2

(1)

2.2

(1)

1.3

(1)

2.3

(1)

1.4

(1)

2.4

(1)

1.5

(1)

2.5

(1)

[5] [5]

QUESTION 3/VRAAG 3 3.1

(2)

3.2

(2)

3.3

(2)

3.4

(2)

3.5

(2)

[10]

QUESTION 4/VRAAG 4

4.1 A B C D

4.2 A B C D

4.3 A B C D

4.4 A B C D

4.5 A B C D

(5 x 3) [15]

TOTAL SECTION A/TOTAAL AFDELING A: 35

NAME/EXAMINATION NUMBER


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NAME/EXAMINATION NUMBER

QUESTION 6.2

(5)

1 50